Pneumatic power hammer



Feb. 1?, 1931. R. E. BATES 1,793,206

PNEUMATIC POWER HAMMER Filed July 50, 1926 4 Sheets-Sheet 1 lnvenTor.

Ralph E. BuTes y/mw MkW ATTys.

Feb. 17, 1931. R. E. BATES PNEUMATIC POWER HAMMER Filed July 30, 1925 4 Sheets-Sheet 2 lnvenTor. Ralph E. BGTeS r m I M 13 W WWW ATTys.

Feb. 17, 1931. R. E. BATES 1,793,206

PNEUMATIC POWER HAMMER Filed July 3 1926 4 Sheets-Sheet 3 R. E. BATES Feb. 17, 1931'.

PNEUMATIC POWER HAMMER 4 Sheets-Sheet 4 Filed July 30, 1926 lnvenTor. Ralph E. Bufes ATTys.

Patented Feb. 17, 1931 UNITED STATES PATENT orties RALPH E. BATES, OF WEST MEDFORD, 'MA SSACHUSETTS, ASSIGNOR T0 WILLIAlVlIS,

WHITE & COMPANY, OF MOLINE, ILLINOIS, A CORPORATION PNEUMATIC POWER HAMMER Application filed July 30, 1926. Serial No. 126,033.

This invention relates to pneumatic power hammers.

In the particular type of hammer to which my invention is applied, the principal elements oi the hammer are all incorporated in a main frame.

In the upper section of the frame is a hammer cylinder in which reciprocates a piston rigidly secured to a ram by means of which the hammer mounted on the lower end of ti e ram is given its motion toward and from the anvil. The anvil is set in a foundation directly beneath the hammer. In the lower section of the frame is a power cylinder containing a piston which is reciprocated within a cylinder by a motion received from a crank and connecting rod.

Power may be delivered to the crank in any convenient way. I have chosen to show herewith tight and loose pulleys adapted to be rotated from a belt connectedto a source of power.

Both cylinders are double acting, that is to say, both the up and down strokes of the pistons are employed to do effective work in the operation of the hammer. The two cylinders are connected by a system of conduits the action of the air pressure is the suction due to the presence of a partial vacuum within the cylinders at certain periods in the cycle of operation of the machine.

The principal object of my invention is to provide a pneumatic hammer of the abovedescribed type which is composed of a minimum number of parts and is of a highly efiicient design, thus producing a machine which will be economical to manufacture and to maintain in operation.

An add tlonal ob ect of my invention is to produce a pneumatic hammer whlch will be cement in em a d rigid. by n pe at ns condition where the device is delivering'its full capacity of hammer blows, which blows may be var ed from a maximum to a very light blow, second, where the hammer 1s lifted and held in its uppermost position and, third,

where the hammer is held down against the work, thus vising or clamping it between the iammer and anvil.

Another object of theinvention is to pro-' vide a doub'leacting power cylinder to. be used in the above described power hammer in which both the up and down strokes are used to do effective work in the operationof the machine with a consequent gain in operating efficiency. v

A further object of the invention is to provide a construction in which the frame of the macl ine is in two main sections, the top section containing the hammer cylinder and having formed integral therewith certain of the communicating conduits between the power Y and hammer cylinders and also forming a closure for the power cylinder, the lower section containing the power cylinder and havingiormed therein a conduit communieatingv with the lower end of the power cylinder, the lower section also forming a closure for thehammer cylinder.

Other objects and features of the invention will more fully appear fromthe following description and accompanying drawings and will be pointed out in the claims.

In the drawings I V Fig. 1 is aside elevation of a pneumatic hammer embodying my invention.

Fig. 2 is an enlarged fragmentary sectional view through the hammer cylinder,

on line W. act:

through the controlling valve and sleeve while the valve is in the position of full blow.

Fig. 5 is a sectional view taken on the line 5-5 of Fi 4.

Fig. 6 is a sectional view taken on the line 66 of Fig. 4.

Fig. 7 is a sectional view taken on line 7-7 of Fig. 4.

Fig. 8 is a sectional view on line 88 of Fig. 4.

Fig. 9 is a side elevation of the controlling valve sleeve.

10 is a plan View of the controlling valve sleeve.

Figs. 11, 12, 13 and 14 are cross sectional views of the controlling valve and sleeve with the controlling valve in a position which acts to elevate the hammer.

Fig. 11 is a sectional view taken on line 5-5 of Fig. 4.

Fig. 12 is a sectional view taken on line 66 of Fig. 4. 7

Fig. 13 is a sectional view on line 77 of Fig. 4.

Fig. 14 is a sectional View taken on line 88 of Fig. 4.

Fig. 15 is a section taken on line 5-5 of Fig. 4.

Fig. 16 is a section taken on line 6-6 of Fig. 4.

Fig. 17 is a Fig. 4.

Fig. 18 is a section taken on line 8-8 of Fig. 4.

Fig. 19 is a section taken on line 1919 of Fig. 4.

Fig. 20 is a sectional view on line 20-20 of Fig. 1.

The main frame of the machine consists of upper and lower sections 1 and 2 which are bolted or clamped together in any suitable way at In the upper section is formed the hammer cylinder 4 within which reciprocates a piston 5 rigid with a ram 6. A continuation 7 of the ram extends into and has a close running fit in a supplementary cylinder 8. The continuation 7 of the ram has two flat faces 9 which prevent the ram from rotating. The ram 6 has a-- accurate hushed hearing 10 formed in an extension of the lower section 2 of the frame. This hearing, which is extra long forms a substantial seal against leakage of air from the hammer cylinder.

Due to the fact that the continuation 7 of the ram fits the supplementary cylinder 8 closely, a certain amount of air is trapped within the supplementary cylinder and put under compression by the upward motion of the ram6. Substantially half way up in the supplementary cylinder 8 is an air conduit 9 open to the atmosphere through which air escapes during the upward movement of the continuation 7 of the ram until the latter reaches the conduit 9, which is then closed section taken on line 77 of by the continuation 7 and further upward movement or" the latter compressses the re maining air in the supplementary cylinder.

n. head 10 bolted upon the upper cut of the supplementary cylinder 8 in which is mounted a cheer valve 11. A seat 12 is formed in the lower face of the head 10 against which the valve 11 is held by a compression spring 13 surrounding the Vdlu". stem and seated at one end on a. collar 14 on the end oi? the valve in and a t the other end upon a perforated supporting web 15 integral with the head 10. collar 14 is formed with an overhanging shirt which covers the perforations in the supporting web 15 excluding dirt therefrom.

One function oi the check valve 11 and supplementary cylincer S is to cushion the 1 ward moven'ient of the rain 6. 1 traps the air under compression and holds the pressure until upon the downward movc ment oi t 1e continuation T of the ram a pressure oelow atmospheric may be created in the cylinder 8 at which time the valve 11 will open and thus prevent any drag upon the ran. due to a vacuum in the cylinder 8. The trapped. air in the cylinder 8 will cause the ram to come to rest gradually and by the reexpans n of the air the ram will be started on its downward movement.

Tie power cylinder 16 is formed integral the base section 2 and has a reciprocat 3lStOl1 17 fitted therein which is provided 1 L011 rings 18. The piston 17 has a The valve nion 17a of smaller diameter which a close running fit in the head of the cylinder which provides a suiiicient seal against escaping air. The piston 17 is reciproeated by a crank 19 and connecting rod c. One end of the connecting rod 20 has a bearing;- on a crank pin 21 upon the cranl; 1 at the other end it has a bearing; upon. mounted on the piston 17. The i is mounted upon a 2ft jourat one end in the base section 2 and l .1 end in a bearing block :24 ilT'lQd integral platform member The ma may be rotated lyy any suitable means ant. r h a ve he ein shown a fast and loose puli Y 2o and mounted thereon and adapted to receive pow r from any suitable s u'cc.

.he end oi the ram 6 is mounted the hanrne head to which may be secured the die 29. Directly beneath the hammer head is the anvil upon which is mounted acomplementary die member 31.

i controlling valve 3.-

mounted for rotation within a valve sleeve 33, which in turn is mounted in an aperture 34 extending all the way through tne upper section 1 of the frame. This sleeve is held against rotation by a. key 3 A short shaft 36 is fixed in the end of the valve and extends through, and has a. hear ng in, a plate 37 bolted to the frame section 1 and extending a short distance witl1- Another conduit 5% leads in the aperture 34'. The handle 38 is secured in a cut-away portion ll of the valve sleeve 33. This cut-away portion is of the proper dimension and location to stop rotation of the valve at the limitof its motion in either direction.

T he action of the hammer is con trolled by various conduits in the valve which cooperate with condui s in the sleeve and communicating conduits in the upper'and lower end of the power and hammer'cylinders, the details of which will be described. later. A further element which cooperates with the controlling valve 32 is a check valve l2 which is mounted in av frame 4:3, which in turn is inserted in a chamber 44 and held therein by bolting a flange integral therewith to the upper section of the frame 1. The check valve 4-2 is held upon its seat l5 by a compression spring 46 seated at one end against an adjustable collar .l'l'upon the valve stem and at the .other end against a wall 43 integral with the frame Extending from the wall $8 is a long boss 49 through which the valve stem extends and is guided and-which, together with the wall 48, prevents air from escaping from the chamber 50. The chamber 50 is isolated from the chamber a l by the valve l2.

The purpose of the valve sleeve 33 is merely to provide a means of readily restoring a good fit after the valve and sleeve have become worn. lt will be noted that the conduits in the sleeve 33 register with the various conduits leading to the diti'erent parts of the machine. Consequently the conduits in the sleeve and the ()Olltdllll-S registering therewith will be considered as and referred to by a single character.

The controlling valve 32 has a relatively large. conduit 5l out of which leads another conduit 52. A conduit'53 of the same lon itudinal dimension as the conduit 51 leads 50' the lower end of the power cylinder 16 and is always in communication with the conduit 51. to the lower end of the hammer cylinder l and by rotation of the controlling valve may be brought into relation with various other conduits, as will hereinafter more fully appear. Another conduit 55 communicates with the chamber 50v and may be made to register with the conduit only, A conduit 56 in the valve 32 registers with a conduit 57 leading into the chamber ll. l l hile the valve 32 is in the elevating position, which will hereinafter be] describe-dith conduit 5? will communicate with the condui 54 through the conduit 56 in the valve.

i i At all other positions of the valve 32 the conduits 56 and 57 have no function.

Leading out of the top of the power cylinder 16 is a conduit which communicates at all times with the conduit 59 in the valve 32.

Another conduit 60 leads to the top of the hammer cylinder 4 and communicates with the conduit 53 at certain positions of the controlling valve 32 which will be explained later. a oy-pass from the chamber ll into the conduit 58 and thence to the upper end of the hammer cylinder, while the valve in the position. that will later be described as a vising position.

an exhaust conduit 62 leads into a chai ber 63 which has an outlet to the atmos he e 64:. T he chamber 63 is made sutliciently large to constitute an effective mufiier which will thus quiet the noise of the exhausted air.'

This exhaust conduit communicates with the conduit 59 in the valve 32 at certain times and is closed other times. A conduit 66 serves as a bypass between the conduit 54- leading to the bottom of the hammer cylinder and the conduit 59 in the valve whenthe valve is in the vising position. i

The control valve 32 may be operated by the handle 38 or by lever 67 pivoted at 68 which acts to operate the handle 38 through a removable connecting member 69 between the handle 38 and one end of the lever 67. A further means of operating the control valve is provided by a foot-actuated lever 70 pivoted at 71 and having a connecting; linl: 72

interposed between the lever 70 and the lever 67 by means or" which the motion'of the lever 70 is transmitted to the lever 67 and thus through the connecting member 69 to the handle 38. By disengaging the member 69' from the handle 38, the device may be operated from tl e latter independently of the lovers 70 and 67. The extreme upward position of lever 70 causes the hammer to be raised and hole away from the work while" the extreme downward position of the lever is the position of full blow. It is necessary therefore to disconnect the connecting mcmber 69in order to throw the valve into visingi position. Such an arrangement pr .vents the operator from unintentionally using the vising position and thus simplifies the operation of the hammer si ice the other and more important functions can be entirely controlled by a comparatively slight motion of the controlls without attempting to avoid the vising position.

There are three. maj or positions of the control valve 32 which result in certain operating conditions ofthe hammer. All intermediate positions cause a gradual change from one condition to another. The three major operating conditions Wlll be calledfull blow. elevating and vislng.

At the full blow condition the hammer is 7 cylinder 16.

striking its full length of strol -re and with its maximum force. The piston 17 is reciprocated continuously by tl e crank 19 and the connecting rod 20. Referring-particularly to Figs. 2, 5, 6, 7 and S, which show the valve in full blow position, it will be apparent upon the downstroke of the piston 17 that air under pressure will be forced through the conduit the .ive conduit o1 and thence into the lower end or" the hammer cylinder through conduit 5%, thus raising the piston 5. As the piston 17 descends, a partial vacuum is created in the top of the It will be noted-that at this time the conduit 58 leading to the top of the cylinder 16 is in communication with the conduit 60 leading to the top of the hammer cylinder through the valve conduit 59. Thus a reduction of pressure is brought about above the piston 5, thus raising the hammer 28.

Upon the upstroke of the piston 17, a reversal of the above operations takes place. Air under pressure from the top 01"? the cylinder 16 is forced into the top of the hammer cylinder 4:, forcing the piston down, which action is supplemented by a reduction of pressure under the piston 5 due to the vacuum cr ated in the lower end of the cyl inder 16 by the upstroke of the piston 17. At the top of the upstroke of the piston 17, the air pressure is immediately relieved and drops to atmospheric level by escaping through conduits 7 3 located near the top of the piston 17 as they register with conduits 74 formed in the top of the cylinder 16. The escaping air passes out through the interior of the piston 17 which is open to the atmosphere. Similarly atmospheric pressure is restored in the lower end of the cylinder 16 when perforations in the lower section of the piston 17!; are uncovered at the top of the upstroke of the piston 17.

This restoring of atmospheric pressure at the end of both the up and down strokes of the piston 17 has the effect of making the hammer work faster and more efficiently. The elasticity of the air, if the air were wholly confined, would make the action of the hammer sluggish. If the high pressure at the end of the upstroke were not reduced, it would merely expand upon the downstroke and have little or no effect upon the piston in the hammer cylinder. Lik wise if the vacuum in the lower end of the cylinder 16 were not restored to atmospheric pressure, hardly any ei'i'ective work would be done upon upon the next succeeding stroke of the piston 17.

lVe will next proceed to describe the condition where the hammer is elevated and held in its elevated position.

Figs. 11, 12, 18 and 14 show the control valve 32 in the proper position to elevate the ram.

Upon the downstroke of the piston 17 the air under pressure passes through conduit into conduits 51 and 52 of the valve and thence into the chamber 50 through the conduit 55. This air under pressure forces its way past the check valve 42 into the chamber 4%. and from there into the conduit 57 through the conduit in the valve and out through the conduit 5 1 to the lower end of the hammer cylinder which raises the hammer. It will be noted that with the valve in the present position, both the conduit 60 from the top 01 the hammer cylinder and the conduit 58 from the top of the power cylinder are in communication with the exhaust conduit 62 through the conduit 50 in the valve. The result of the above described relative positions of conduits causes the upper e id of the pow r cylinder to have no effect on the hammer as the air simply blows in and out of the exhaust conduit 62. The fact that the conduit 60 is open to the at inosphere allows the hammer to be raised freely.

When the power piston 17 rises, a vacuum will created in the conduit 53, but this vacuum will have no effect upon the piston 5 as the check valve 42 prevents any negative pressure from passing into the lower end of the hammer cylinder 4;, thereby nullifying the upstroke of the power piston 17 and making e 'i ecti e the pressure or downstrokes oil? the piston 17, the result of this being that the hammer will rise and remain in its elevated position. G11 the upstrokes of the power piston 17, the air merely expands idly, producing no ell'ect.

It may be judged from the previous explanation of the action of the continuation of the ram 7 and the supplementary cylinder 8 that the piston 5 can never reach the top of the hammer cylinder. --Iowever, there is a gradual leakage of air that takes place in the cylinder 8 through the valve 11 and between the continuation of the ram 7 and the walls of the cylinder 8, thereby permitting the piston 5 to gradually rise to the top of the cylinder.

The next condition is the vising condition wherein the hammer is lowered and held down on the work, vising or clamping it against the anvil.

Figs. 15, 16, 17, 18 and 19 illustrate the valve in the vising position. As the power piston 17 descends, air under pressure passes into the conduit 53 through the conduits 51 and 52 of the valve into the conduit communicating with the chamber It now passes through the check valve 42 and into the chamber 44 and thence out of the only available conduit 55. It then passes into the conduit 60 leading to the upper end of the hammer cylinder through the by-pass conduits 61 in the valve 3 The result of this is to force the piston 5 downwardly. The vacuum created by the upstroke of the piston 17 is checked by the check valve 42 in the same manner as above described in the elevating condition. The result of the foregoing is that the down strokes oi? the power piston 17 are used to force the hammer down upon the anvil while the upstrokes of the power piston are nullified by the action 01" the check valve, which results in holding the hammer down against thework.

As shown in Fig. 18, the conduit 58 is in communication with the exhaust conduit 62 through the conduit 59, thus allowing the air in the top of the power cylinder 16 to pass freely in and out of the exhaust conduit 62. In Fig. 17 it will be noted that the conduit 66 communicates with the conduit 54 leading to the lower end of the hammer cylinder. The conduit 66 also communicates with the conduit 59 in the valve 32 which is open to the exhaust conduit 62 and the atmosphere. Thus the air beneath the piston 5 is vented to allow it to descend.

As has been indicated previously, the hammer may be held in any position throughout its stroke and may be made to deliver a blow of varying power by setting the controlling valve 32 at various points intermediate of the three major positions.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. In a pneumatic hammer, the combination with a power cylinder having a driven piston therein, a-hammer cylinder, a piston reciprocable therein, a ram rigid with the latter piston, a hammer upon the end of the ram, a valve seat, conduits connecting said seat with the ends of the cylinders and the atmosphere and a valve movable on said seat to control the passage of air in said conduits, of an enclosed supplementary cylinder mounted upon the end of the hammer cylinder, an elongation of the ram reciprocable within the supplementary cylinder and acting as a piston therein, an inwardly-opening check valve within the supplementary cylinder communicating from the chamber above the ram to the atmosphere and maintaining the pressure in said chamber at or above atmospheric pressure so that upon the upstroke oi the hammer air is compressed within said chamber causing the hammer to come to rest gradually and by the re-expansion of the air reversing the motion of the hammer.

2. In a pneumatic hammer, the combination with a power cylinder having a driven piston therein, a hammer cylinder, a piston reciprocable therein, a ram rigid with the latter piston, a hammer upon the end of the ram, conduits communicating between the cylinders, and means to control the passage of air in said conduits, of an enclosed supplementary cylinder mounted upon the end of the hammer cylinder, an elongation of the ram reciprocable within the supplementary cylinder and acting as a piston therein so that upon the upstroke of the hammer air is compressed within said chamber causing the hammer to come to rest gradually and by the re-expansion of the air reversing the motion of the hammer.

8. In a pneumatic hammer, the combination with a power cylinder having a driven piston therein, a hammer cylinder, a piston reciprocable therein, a ram rigid with the latter piston, ahammer upon the end of the ram, conduits communicating between the cylinders, and means to control the passage of air in said conduits, of an enclosed supplementary cylinder mounted upon the end of the hammer cylinder, an elongation of the ram reciprocable within the supplementary cylinder and acting as a piston therein, an inwardly opening check valve within the supplementary cylinder communicating from the chamber above the ram to the atmosphere and maintaining the pressure in said chamher at or above atmospheric pressure so that upon the upstroke of the hammer air is com pressed within said chamber causing the hammer to come to rest gradually and by the re-expansion o1 the air reversing the motion of the hammer.

4. In a pneumatic hammer, the combination with a power cylinder having a driven piston therein, a hammer cylinder, a piston reciprocable therein, a ram rigid with the latter piston, a hammer upon the end of the ram, conduits communicating between the cylinders, and means to control the flow of air in said conduits, of an enclosed supplementary cylinder mounted upon the end of the hammer cylinder, an elongation of the ram reciprocable within the supplementary cylinder and acting as a piston therein, and means to maintain the pressure in the chamber above the ram at or above atmospheric pressure so that upon the upstroke of the hammer air is compressed within said chamber causing the hammer to come to rest gradually and by the re-eXpansion of the air reversing the motion of the hammer.

In testimony whereof, I have signed my name to this specification.

RALPH E. BATES. 

